A hydrofoil, or foil for short, is a fin-like structure used to direct fluid flow. Foils, fins, centerboards, skegs, and hydrodynamic keels can optimize lift, reduce drag, and stabilize a vessel hull or vehicle body (hereinafter generically referred to as “hulls”) when mounted at a suitable angle of attack relative to the oncoming fluid. Foils also enhance drive and maneuverability in the fluid, acting in some ways like the friction of wheels on a solid surface. Here, a “fluid” may be either water or air.
Related fields include foils that vary the inherent fluid-dynamic characteristics of attached vessel hulls or vehicle bodies by deriving lift, altering trim, reducing turbulence, or diminishing wave resistance; in particular, removable fins and foils for surfboards, sailboards, and pleasure or sport vessels.
Foil mountings can be permanent or removable. For example, a foil can be permanently attached with fasteners or adhesive to an inner layer partially constructed hull, then both foil and hull can be overcoated or overwrapped with outer layers such as fiberglass and resin. Removable foils can be inserted and withdrawn from sockets built into the hull, and fixed in place with fasteners or the like. Removable foils allow a user to change the number, type, or position of foils, adapting the hull to different fluid-dynamic performance demands imposed either by different surrounding conditions, different users, or different types of use. They also allow a user to quickly replace a damaged foil, or remove foils for easier storage or transport.
These removal and replacement operations can take place on beaches and shores, or sometimes even in the water. In these settings, mountings that require few or no tools to remove and replace a foil are convenient. Many users will sacrifice convenience if the foils are likely to wholly or partially self-detach in strong or turbulent currents. On the other hand, some foils are intentionally made frangible so that a substantial impact causes them to break away rather than damage the hull or injure the user or a nearby person or animal.
Rigid mountings and rigid foils can be simple and rugged, but they affect maneuverability when rapid turns are desirable or when the flow direction of the ambient fluid may change suddenly. The fluid-pressure drop causes bubble formation in the turbulent water on the leeward side of the foil, and the resulting cavitation or “crabbing” increases drag and can cause loss of control of the board or other craft; if the foil leaves the water completely, stall occurs, and there is a loss of control similar to a land vehicle's hydroplaning in a water puddle. Multiple foils mounted rigidly at different angles aid in turning, but can create drag that reduces the speed of the craft while carving into the face of a wave or during straight-line travel. In a curve, a fin angled at a non-optimal orientation (not tangent to the curve) also increases drag. In addition, water leakage or shocks associated with repeated torsional stresses over time may cause strain damage to the foil mounting, or hull.
The present mounting options for hydrofoil mounts are not strong enough to withstand the extreme forces exerted by the foil in the surf. Additionally, they require too many installation steps and add weight without adding strength. It is therefore an objective of the present invention to introduce an apparatus that combines both a plate mount and tuttle mount in a one-piece mounting system. The mounting system is stronger and easier to install than each system installed individually.
The present invention is compatible with most hydrofoils on the market today. Some Foil companies sell foils with a “Deep Tuttle” mount that can be installed in a center Tuttle Box mount on the present invention. Other companies sell foils with a “Plate Mount” that can be installed into two US Box tracks mounted with 9 cm spacing using four plate mount screws and plates. The present invention is compatible with both types of systems and combines them both in a unit that is strong and easy to install.
Assembly of the present invention involves the following steps: A rectangular opening in the shape of the present invention is cut out of a surfboard or similar craft using a router. The present invention is glued into the board with a carbon base plate flush to the bottom laminate of the board; using thickened resin or a foaming adhesive such as Gorilla Glue. Once glued, the top of the present invention is sanded down to be flush with the top deck layer of the board. The installation area is then glassed over with several layers of fiberglass and/or carbon fiber with epoxy resin on both sides (both on the deck and the bottom of board). The openings for the Tuttle mount and the two plate mount tracks are cut out on the bottom and the two screw holes openings are cut out of the deck once the laminate has fully cured. Installed this way, the present invention provides a one-piece universal mount that is easier to install and stronger than other available installation options.